Wraparound battery and heater

ABSTRACT

A reserve battery acting as a heating element is designed for heating the contents of a food package or container. The battery is energized at the time the contents are to be heated by releasing the electrolyte into the electrode compartment of the battery. The battery may be designed of flexible electrodes and separator and is readily wrapped around the package or container of the material to be heated. Another configuration may be inserted into a cavity in the package or container. Still another configuration may be sandwiched between two flat objects to be heated. The battery is effectively short circuited upon itself so as to generate heat evenly over the surface of the package or container. In the wraparound configuration of the battery, a special flexible insulating cover is built into the battery to reflect heat which would otherwise escape into the surrounding atmosphere and also provide protection in handling after activation.

United States Patent Inventors John C. Bogue 1036 S. 1st St., SantaMonica, Calif. 91006; Robert I. Sarbacher, 101 Ocean Ave., Arcadia,Calif. 90402 App]. No. 885,261

Filed Dec. 15, 1969 Patented Nov. 30, 1971 WRAPAROUND BATTERY AND HEATER3,5 l3,827 5/1970 Egger ABSTRACT: A reserve battery acting as a heatingelement is designed for heating the contents of a food package orcontainer. The battery is energized at the time the contents are to beheated by releasing the electrolyte into the electrode compartment ofthe battery. The battery may be designed of flexible electrodes andseparator and is readily wrapped around the package or container of thematerial to be heated. Another configuration may be inserted into acavity in the package or container. Still another configuration may besandwiched between two flat objects to be heated The battery iseffectively short circuited upon itself so as to generate heat evenlyover the surface of the package or container. in the wraparoundconfiguration of the battery, a special flexible insulating cover isbuilt into the battery to reflect heat which would otherwise escape intothe surrounding atmosphere and also provide protection in handling afteractivation.

PATENTEUNUV 30197! 3, 623 .471

III IlJJ /50 INVENTORS JOHN C; BOGUE. ROBERT l. SARBACHEP FIG? BYATTORNEY BACKGROUND OF INVENTION There are a number of instances whereit is desirable to heat the contents of a package or container as forexample the contents of a can of soup in a lunch or picnic basket whereit is desired to use such contents immediately after heating, or where asoldier desires to heat a C-ration allotment, but has no heatingfacilities or is unable to start a fire because of detection. Suchinstances may also arise when power for heating such contents are remoteand not reasonably accessible as in new building construction in remoteareas. Some building materials such as vinyl or asphalt tile may requireheating in cold weather before installation. There are of course manyother instances where heat may be required and conventional heat sourcesare either not available or for some reason not desirable.

This invention provides a heat source that can be used in many differentsituations including but not limited to those situations whereconventional heat sources are not available or not desirable. In otherwords, this invention provides a heat source that has general utilityand is particularly useful where heat is to be applied to objects suchas packages, cans of food, fiat objects and the like.

SUMMARY OF THE INVENTION The present invention relates to the design ofelectrical heating elements wherein the reserve battery electrodesthemselves generate the heat that is produced when the battery isenergized. In particular it relates to such batteries whose shelf lifeprior to activation is essentially unlimited and whose life onceactivated is sufficiently long to produce the heat required for thespecific application to which it is placed.

One aspect of the heating elements of the present invention is the useof reserve batteries. Reserve primary batteries are known to the art.They are batteries wherein the electrodes are fully assembled foroperation, but the electrolyte is held in reserve in a separatecontainer which may be within the battery housing. Since there is noconsumption of the electrodes under these circumstances the shelf lifeof the battery is essentially indefinite. However, once the electrolyteis released from its reserve container, such as by mechanical puncture,explosive squib rupture, pressure sufficient to rupture, or any othermeans as are well known in the art, the battery is activated, andthereafter has a limited life.

In accordance with the present invention, a series of shortcircuitedreserve primary batteries are employed in parallel and have a pressureactivation system or a mechanical puncture system incorporated torelease the electrolyte when desired.

Three methods for utilizing the short circuited primary reserve batteryare described. One of these methods describes a system of batteriesdesigned to be wrapped around the material to be heated. Another methoddescribes a system of batteries designed to be sandwiched between twomaterials to be heated and the third method describes a single batteryof cells which may be inserted in a cavity in a container the contentsof which is to be heated.

It is therefore one object of the present invention to provide heatingelements requiring no separate or outside power source to heat thecontents of a package or container.

Another object of this invention is to provide heating elements having aspecific heat content capability to raise the temperature of thecontents of a given package or container a specific amount.

Still another object of this invention is to provide a flat flexibleheating element which may be wrapped around the object to be heated.

Still another object of this invention is to provide a flat, flexibleheating element which may be sandwiched between two objects to beheated.

Still another object of this invention is to provide a self-containedheating element which may be inserted in a cavity in a container, thecontents of which are to be heated.

Other objects and advantages of the present invention will becomeapparent to those skilled in the art from a consideration of thefollowing exemplary detailed description of the specific embodiment ofthe invention in conjunction with the drawings provided.

LIST OF FIGURES FIG. 1 is a schematic exploded view of a partial batteryof cells as contemplated by the present invention for one form of a wraparound heater.

FIG. 2 is a schematic exploded view of a partial battery of cells ascontemplated by the present invention for another form of a heater.

FIG. 3 is a face view of a fragment of the separator used in these cellsin accordance with the present invention.

FIG. 4 shows two views of the fiat construction of the battery, plan,and side view in accordance with the present invention.

FIG. 5 is a horizontal cross-sectional and fragmentary detailed view ofa partial battery embodying the principles of the present invention.

FIG. 6 is an illustration of one effective mode of arranging the heaterand electrolyte container in accordance with the present invention.

FIG. 7 is an illustration of another effective mode of arranging theheating elements in a container in accordance with the presentinvention.

FIG. 8 is an illustration of one form of reserve cell assembled inaccordance with the principles of the present inven- IlOn.

DETAILED DESCRIPTION OF INVENTION For the purposes of illustration, thepresent invention is described herein as embodied in amagnesium/magnesium perchlorate, lithium perchlorate/mercuric oxidecell; however, the features of this invention are not limited to thiscell.

In the exploded schematic illustration of FIG. I, a partial battery ofcells is illustrated showing one anode and one cathode.

The anode 11 is formed from magnesium sheet stock, such as produced byDow Chemical Company under the designation AZ-2l or AZ-3l, preferablyabout 0.004 inch in thickness. The cathode 12 comprises a stainlesssteel sheet 13 approximately 0.00l inch thick as a structural baseelement, one side of which is coated with a mercuric oxide paste 14. Athin absorbent fibrous separator 15, which may be a filter paper stockis interposed between the anode 11 and the cathode l2 and carries theelectrolytic solution when activated.

The physical structure of the separator 15 is illustrated in face viewin FIG. 3. This element 15 is made foraminous by punching holes 18 therethrough. Optimumly, each hole 18 is about one-sixteenth inch indiameter, and they are uniformly distributed with a spacing thatprovides about 20 holes per square inch of surface area.

The stainless steel element 13 is coated with the mercuric oxide paste14. This paste is prepared by mixing mercuric oxide with carbon black toimprove conductivity in the weight ratio of about 9.5 to I together witha small amount of a suitable binder, such as about 0.05 percent byweight of carborymethylcellulose. This mixture is ball milled dry forabout an hour and then enough water is added to make a thick paste andit is further ball milled for an additional hour. The resultant mixtureis spread in a thin layer about one sixtyfourth inch thick over thesurface of the stainless steel element 13 prepared as above described.Cathode 12 thus prepared is dried in an oven at about 200 F. for about30 minutes with the separator 15 pressed into the mercuric oxide pasteso that the holes 18 in the separator are filled with paste.

In the wrap around configuration of, an battery the insulating plasticsheet 16 (FIG. 1) is coated on one side with a thin aluminum film 17which may be evaporated on the plastic by well-known methods. Thealuminum serves to reflect heat generated in the battery back into thecell and to the container or package about which the battery is wrapped.The surface formed by the stainless steel element I3 is one side of thebattery, while the plastic sheet 16 is the other side forming in thismanner the container of the cells. All sides of the battery are sealedby a plastic strip which is welded to the plastic 16 on one side and thestainless steel 13 on the other.

FIG. 4 represents two views of the assembled series of cells. Theelectrolyte container is a plastic bag 20 running the length of the flatsheet 21 with partially perforated openings along the lower edge 22.When pressure is applied to the bag 20 the electrolyte 19 is releasedand if held in the proper position, upright, will flow down the channels23 and be absorbed by the separator 15, in this manner activating theheating action.

The holes 18 in the separator 15 effectively form short circuits for thecells, and because of their uniform spacing produce virtually constantheat gradient along the flat surface of the stainless steel element 13and the magnesium anode 11. When the battery is wrapped around thecontainer to be heated, the heat generated in the battery is transmittedthrough the stainless steel 13 to the container and then to the materialto be heated.

The electrolyte 19 may employ a 5 normal aqueous perchlorate solution ofmagnesium and lithium in the ratio of 95 to 5 by weight.

The cross-sectional view of the battery is shown in FIG. 5 where thecomponents 13 through 17 are indicated. The separator 15 is cut insections about 1 inch wide in assembly and spaced along the length ofthe battery as shown by the dotted line so as to create the channels 23through which the electrolyte 19 may pass when released Small metallicor plastic rivets 26 may be inserted holding the outside surfaces of thebattery together. These should pass through the center of the width ofthe separator 15 and about 2 inches apart, in length.

If it is desired to heat two reasonably flat objects at the same time sothat the battery may be sandwiched between them, then the plasticmaterial 16 with aluminum coating 17 is not required.

In this event the electrode arrangement may take the form indicated inFIG. 2 where the stainless steel element 13 is coated on both sides withthe mercuric oxide paste 14 to form the cathode electrode. It may bedesirable to punch holes in the stainless steel element 13 in a similarmanner as described for the separator 15. In this configuration theheating element is enclosed on both sides by the magnesium anodeelectrodes 11 which form the enclosure for the battery-heater. The edgesare sealed as described for the wrap around heater FIG. 4. Also, rivetsbinding both sides together spaced as described for the wraparoundheater may be inserted either of metal or plastic.

In the event it is desired to fasten the battery on a can or containerso that it may be used as a label 35 for the can, an arrangement such asshown in FIG. 6 may be used. Here the electrolyte 19 may be contained ina compartment in or attached to the bottom of the can as indicated. Inorder to release the electrolyte 19 into the channels 23, a circularplastic disc 31 with sharp projections 32 is included in the electrolytecompartment 33 in such a manner that by depressing the bottom of thecontainer 34 the projections 32 will break the seal between theelectrolyte compartment 33 and the channels 23 permitting theelectrolyte 19 to enter the separators 15 and activate the battery.Inversion of the can will aid the flow of electrolyte.

By manufacturing the electrodes in a rectangular or disc configuration,the battery may be assembled in the form of a rectangle or cylinder.Holes in the separator between anode and cathode effectively shortcircuit the battery when activated so that it becomes an effective heatsource. It should be noted that these batteries have no externalterminals. Depression of a plunger will activate the battery when theassembly of battery and container is inverted. FIG. 7 shows across-sectional view of such a cell 40 placed in a cavity 41 in thecontainer 42. Cell 40 can be as thin as one-sixteenth of an inch.

A cylindrical battery-heater element is indicated in FIG. 8. The anodes,cathodes and separators are here, made in the form of a disc with a hole44 in the center of each to permit the electrolyte to reach theinterelectrode space occupied by the separator 15 as quickly as possibleafter activation by pressing the plastic top 43 of the metal container45. The sharp point 46 breaks the electrolyte container 47 releasing theelectrolyte 19 into the electrode compartment 48 thus activating theheating element.

Having thus described the present invention by reference to a specificembodiment thereof, it is not intended that the invention be limitedthereto for numerous variations and modifications will be apparent tothose skilled in the art. Such modification and variations as areembraced by the spirit and scope of the appended claims are contemplatedas being within the purview of the present invention.

What is claimed is:

l. A heat source comprising: an electrochemical reserve primary cellbattery having an anode, a cathode, a perforated absorbent separatorsandwiched between said anode and cathode in such a manner that saidanode and cathode are in short circuiting contact through saidperforations, and an electrolyte, said electrolyte being stored in arupturable compartment to isolate said electrolyte from said anode andcathode until said heat source is to be activated and means to rupturesaid rupturable compartment to permit the electrolyte to flow into saidabsorbent separator thereby activating said heat source.

2. The heat source as defined in claim 1 wherein said anode forms oneside of the battery container and said cathode forms the other side ofthe battery container.

3. The heat source as set forth in claim 1 wherein said anode and saidcathode are made of materials which are thin and flexible therebyproviding a flexible battery.

4. The heat source as defined in claim 1 wherein said rupturableelectrolyte container is made of flexible plastic and said means torupture said container comprises means to apply pressure to saidflexible plastic container, said flexible plastic container being sopositioned that rupture of said flexible container by said pressureapplication means releases said electrolyte into the anode and cathodeinterelectrode space occupied by said absorbent separator.

5. The heat source as defined in claim I wherein channels are providedbetween the anode and cathode to permit rapid disbursement of saidelectrolyte throughout said separator upon the release of saidelectrolyte from said rupturable container.

6. The heat source as defined in claim 4 wherein said heat source isaffixed to a container as the label for said container.

7. The heat source as defined in claim 5 wherein said heat source isaffixed to a container as the label for said container.

8. The heat source as defined in claim I wherein said anode, cathode andseparator are positioned coaxially and encapsulated to form a heatsource suitable for insertion into a material that is to be heated.

9. The heat source as defined in claim 1 wherein said anode, cathode andseparator are positioned coaxially and encapsulated to form a heatsource suitable for insertion into a cavity formed in a container thatis to be heated.

10. The heat source as defined in claim 4 wherein an insulatory andreflectory material is provided as one side of said battery to aid inthe containment of heat and to provide a means for safe handling of saidheat source after said battery has been activated.

11. The heat source as defined in claim 5 whereiii an insulatory andreflectory material is provided as one side of said battery to aid inthe containment of heat and to provide a means for safe handling of saidheat source after said battery has been activated.

12. The heat source as defined in claim 1 wherein said anode forms bothsides of the battery container thereby providing a heat source that canbe sandwiched between two objects that are to be heated.

1. A heat source comprising: an electrochemical reserve primary cellbattery having an anode, a cathode, a perforated absorbent separatorsandwiched between said anode and cathode in such a manner that saidanode and cathode are in short circuiting contact through saidperforations, and an electrolyte, said electrolyte being stored in arupturable compartment to isolate said electrolyte from said anode andcathode until said heat source is to be activated and means to rupturesaid rupturable compartment to permit the electrolyte to flow into saidabsorbent separator thereby activating said heat source.
 2. The heatsource as defined in claim 1 wherein said anode forms one side of thebattery container and said cathode forms the other side of the batterycontainer.
 3. The heat source as set forth in claim 1 wherein said anodeand said cathode are made of materials which are thin and flexiblethereby providing a flexible battery.
 4. The heat source as defined inclaim 1 wherein said rupturable electrolyte container is made offlexible plastic and said means to rupture said container comprisesmeans to apply pressure to said flexible plastic container, saidflexible plastic container being so positioned that rupture of saidflexible container by said pressure application means releases saidelectrolyte into the anode and cathode interelectrode space occupied bysaid absorbent separator.
 5. The heat source as defined in claim 1wherein channels are provided between the anode and cathode to permitrapid disbursement of said electrolyte throughoUt said separator uponthe release of said electrolyte from said rupturable container.
 6. Theheat source as defined in claim 4 wherein said heat source is affixed toa container as the label for said container.
 7. The heat source asdefined in claim 5 wherein said heat source is affixed to a container asthe label for said container.
 8. The heat source as defined in claim 1wherein said anode, cathode and separator are positioned coaxially andencapsulated to form a heat source suitable for insertion into amaterial that is to be heated.
 9. The heat source as defined in claim 1wherein said anode, cathode and separator are positioned coaxially andencapsulated to form a heat source suitable for insertion into a cavityformed in a container that is to be heated.
 10. The heat source asdefined in claim 4 wherein an insulatory and reflectory material isprovided as one side of said battery to aid in the containment of heatand to provide a means for safe handling of said heat source after saidbattery has been activated.
 11. The heat source as defined in claim 5wherein an insulatory and reflectory material is provided as one side ofsaid battery to aid in the containment of heat and to provide a meansfor safe handling of said heat source after said battery has beenactivated.
 12. The heat source as defined in claim 1 wherein said anodeforms both sides of the battery container thereby providing a heatsource that can be sandwiched between two objects that are to be heated.